One mode of fumigating goods (e.g. cargo/produce) in a transportation container (e.g. an ISO shipping container or another type of intermodal freight shipping container) involves inserting a fumigating gas introduction pipe into the container (e.g. through door seals of the container) and supplying a required amount of gaseous fumigant into the airspace of the container. In some larger containers the volume of the gaseous fumigant required can be as much as six (6) cubic metres. During fumigant introduction into the container, the pressure inside the container increases and the fumigant/air mixture thus becomes pressurised to escape into the atmosphere through imperfections of the container (e.g. this escape may occur through the perimeter of the door seals, through the floor, etc). The fumigant/air mix will continue to escape from the container until the pressure inside the container returns to atmospheric. This inadvertent release of fumigant is undesirable both for environmental and economic reasons. Some fumigants, such as methyl bromide, deplete the ozone layer and are highly toxic to humans.
A reference to such background art is not an admission that the art forms a part of the common general knowledge of a person of ordinary skill in the art in Australia or elsewhere.